Cannot boot, no such file or directory

Hi all,
I'm sorry to drop in with such faint info, but I'm at a total loss here, and don't even know where to begin. I can't even tell tell what version this thing is running.
I've inherited the care of a FreeNAS machine from someone else, as part of a CPA office I manage. I know absolutely zero about FreeNAS, but this is what they are using for their file server. They called me Monday in a panic, saying that they can't access the server. They sent a photo, and I see a message that says (among other things):
mount: /dev/ufs/FreeNASs3 : No such file or directory
mount -o ro /dev/ufs/FreeNASs3 /conf/default/etc failed: dropping into /bin/sh

I've done some searches here, and it seems like maybe FreeNAS is corrupt somehow? They had a bad storm, but they said the machine had been shut down and unplugged prior to any power outages, so I'm not sure what could have happened.

FreeNAS Expert

FreeNAS became 2 projects... this one run by iX Systems and the other one, which was called NAS4Free and then renamed again to Xigmanas.

The disk you're working with there is UFS, which is no longer supported on FreeNAS (this fork and associated forum), so I think your best bet is to head over to Xigmanas and see if you can find some help there. https://www.xigmanas.com/

Aiming to mostly replicate the build from @Stux (with some mods, hopefully around about as good as that link)

... and one playground system I use for VMs and Docker:
CASE: Origen AE X15e
MB: MSI X99A SLI PLUS
CPU: Intel Core i7 5820K - 6 cores
RAM: 64GB DDR4-2133 DIMMs (no ECC on this build... no data I care about losing and no CPU support for it)
HDD: 4x2TB Seagate (some really old ones... it's a miracle they are still spinning)
SSD: 2x500GB Sandisk - mirrored for VM and docker
OS: 2xUltra Flair 32GB (mirror)
FreeNAS-11.2-U5
I will be switching this build to proxmox and swapping around some of my other machines, so will remove it from this list when that's done.
First I want to play with Rancher 2.0 on it for a bit to learn kubernetes... that may take a while.

... and one playground system I use for VMs and Docker:
CASE: Origen AE X15e
MB: MSI X99A SLI PLUS
CPU: Intel Core i7 5820K - 6 cores
RAM: 64GB DDR4-2133 DIMMs (no ECC on this build... no data I care about losing and no CPU support for it)
HDD: 4x2TB Seagate (some really old ones... it's a miracle they are still spinning)
SSD: 2x500GB Sandisk - mirrored for VM and docker
OS: 2xUltra Flair 32GB (mirror)
FreeNAS-11.2-U5
I will be switching this build to proxmox and swapping around some of my other machines, so will remove it from this list when that's done.
First I want to play with Rancher 2.0 on it for a bit to learn kubernetes... that may take a while.